The fuel filter was changed by the first garage, so there were bubbles before that and still bubbles now when it's cold. I just checked the car again a minute ago after i got home from work, the car is nice and warm and running fine and sure enough absolutely zero bubbles in the line. Unfortunately the inlet hose for the fuel filter isn't transparent so i cant tell whether the air is coming from the filter or somewhere before that. Im tempted to get the whole fuel filter and filter housing changed.

If it's cold tomorrow morning and the car is stalling i'll check for bubbles again just to make sure they are there and it's not a coincidence.